“We will appeal tomorrow to the Constitutional Court to lift the house arrest,” lawyer Ismail Cem Halavurt told Reuters on Tuesday.

The evangelical pastor is charged with links to Kurdish militants and supporters of Fethullah Gulen, the cleric blamed by Turkey for a failed coup attempt in 2016. He has denied the accusation – as has Gulen – and Washington has demanded his immediate release.

On Monday, President Tayyip Erdogan said Turkey was determined to fight, within legal and diplomatic frameworks, “this crooked understanding, which imposes sanctions using the excuse of a pastor who is tried due to his dark links with terror organisations.”

Halavurt said he did not expect the constitutional court to make a ruling before the Oct. 12 hearing, “but we want to have completed our appeal before (then)”.

Brunson, who has lived in Turkey for two decades, has been detained for 21 months on terrorism charges and is currently under house arrest.

Donald Trump, who counts evangelical Christians among his core supporters, has become a vocal champion of the pastor’s case.

The U.S. president believed he and Erdogan had agreed a deal to release him in July as part of a wider agreement, but Ankara has denied this.